1. Field of the Invention
The present invention relates to an exhaust system of an engine, and more particularly to an exhaust system in which a cylinder head and an exhaust manifold are integrally formed.
2. Description of Related Art
Generally, an internal combustion engine is equipped with an exhaust system for exhausting exhaust gas that is combusted inside a cylinder.
An exhaust port is formed in the cylinder head so as to exhaust the exhaust gas from the cylinder. The exhaust gas that is exhausted from the exhaust port is supplied to a catalytic converter through the exhaust manifold.
The exhaust manifold is fabricated as a separate component and is assembled to the cylinder head by bolts etc.
The exhaust manifold is exposed to atmosphere and is prepared as a separate member from the cylinder head such that the exhaust manifold cannot be cooled by a water jacket but can be cooled by ambient air.
If the exhaust system for exhausting the exhaust gas from the cylinder to the catalytic converter is compactly designed, the engine compartment can be efficiently used.
Also, the exhaust system has been developed to improve durability thereof and to sustain an appropriate temperature of the exhaust gas that is transferred to the catalytic converter.
However, the exhaust gas is not efficiently cooled such that the exhaust resistance and the fuel consumption increase. In addition, the exhaust manifold is separately assembled to the engine such that the assembly cost increases and the engine compartment structure is complicated. In addition, there is a problem that noise is generated from the exhaust manifold by the exhaust gas.
The information disclosed in this Background of the Invention section is only for enhancement of understanding of the general background of the invention and should not be taken as an acknowledgement or any form of suggestion that this information forms the prior art already known to a person skilled in the art.